Method for modulating the production of a selected protein in vivo

ABSTRACT

A method is provided for use in producing a selected protein in mammalian cells, and to cDNA molecules useful in the method, and fusion proteins produced from expression of the cDNA. In the method, cDNA encoding a fusion protein that includes a mammalian DHFR and the selected protein is introduced into mammalian cells such that it is expressed. The naturally occurring repression of DHFR translation is overcome by treatment of the cells with a folate or antifolate or similar composition. The relief from this repression extends to the selected protein which is the second part of the expressed fusion, such that the treatment results in controllable and enhanced production of the selected protein.

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 60/375,250 filed Apr. 22, 2002, which application is incorporated herein by reference in its entirety.

[0002] The invention disclosed in this application was supported by grants CA-08010 and CA-86438-02 from the National Cancer Institute. The United States Government may have certain rights in this invention.

BACKGROUND OF THE INVENTION

[0003] This application relates to a method for modulating the production of a selected protein in vivo by controllable translational upregulation. The method makes use of cDNA encoding fusion proteins which contain a gene encoding dihydrofolate reductase (DHFR) and a second gene encoding the selected protein.

[0004] In mammals, DHFR levels in vivo are regulated in part because DHFR inhibits its own translation by binding to its cognate RNA within the coding region. This repression of protein synthesis is relieved when antifolates such as methotrexate (MTX) or trimetrexate (TMTX) are administered, leading to renewed protein synthesis.

SUMMARY OF THE INVENTION

[0005] The present invention provides a method for use in producing a selected protein in mammalian cells, to cDNA molecules useful in the method, and to fusion proteins produced from expression of the cDNA. In accordance with the invention, cDNA molecules encoding a fusion protein that comprises mammalian DHFR and the selected protein is introduced into mammalian cells such that it is expressed. The naturally occurring repression of DHFR translation is overcome by treatment of the cells with a folate or antifolate or similar composition. The relief from this repression extends to the selected protein which is the second part of the expressed fusion, such that the treatment results in controllable and enhanced production of the selected protein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 shows an exemplary fusion cDNA in accordance with the invention;

[0007]FIG. 2 shows Western blot results demonstrating increased expression of a DHFR HSV-TK fusion protein in response to antifolate treatment;

[0008]FIG. 3 shows increase in sensitivity to GCV by cells transduced with DHFR-HSV-TK fusion protein;

[0009]FIG. 4 shows increased accumulation of ¹⁴C-FIAU in cells transduced with DHFR-HSV-TK fusion protein;

[0010]FIG. 4 shows that ³H-thymidine incorporation is comparable in cells transduced with DHFR-HSV-TK fusion protein and untransduced cells;

[0011]FIG. 6 shows antitumor response of transduced tumor cells;

[0012] FIGS. 7A-D show GCV sensitivity and TMTX resistance of parental, transduced and TMTX-exposed colon cancer cells; and

[0013]FIG. 8 shows fusion cDNAs containing the EGFP gene.

DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention provides a method for use in producing a selected protein in mammalian cells, and to cDNA molecules useful in the method. In accordance with the invention, cDNA molecules encoding a fusion protein that comprises mammalian DHFR and the selected protein is introduced into mammalian cells such that it is expressed. The naturally occurring repression of DHFR translation is overcome by treatment of the cells with a therapeutic agent that causes DHFR to release from its cognate RNA, for example a folate or antifolate. The relief from this repression extends to the selected protein which is the second part of the expressed fusion, such that the antifolate treatment results in controllable and enhanced production of the selected protein.

[0015] Thus, in a first aspect, the present invention provides a cDNA molecule encoding a fusion protein that comprises mammalian DHFR and a therapeutic protein. The sequences of several types of mammalian DHFR are known in the art, including dog, monkey, rat and mouse (Seq. ID. Nos. 1-4, respectively). The wild-type sequence of human DHFR is also known. (Seq. ID. No. 5) Masters et al., Gene 21: 59-63 (1983). The mammalian DHFR included in the cDNA molecule may be a wild-type sequence, or it may be a mutant form in which one or more amino acids are changed to alter resistance to antifolates such as methotrexate.

[0016] In one set of mutations, the mutations is such that the mutant DHFR has increased resistance to methotrexate. Methotrexate can inhibit the activity of such mutants to some extent, and remains effective to remove the DHFR protein from the RNA, leading to a resumption of translation. In addition, the mutant DHFR can confer resistance to transfected cells, allowing for usage of higher doses of methotrexate without killing the cells, and for selection of transformed cells. In particular, the DHFR encoded by the cDNA may be a mutant form of human DHFR that differs from wild-type human DHFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence. As used in the specification and claims of this application, the term “corresponding” refers to an amino acid residue that occupies the same function position (e.g., a position within the active site) even though the amino acid number may be different as a result of insertions or delations elsewhere in the protein.

[0017] International Patent Publication No. WO94/24277, which is incorporated herein by reference, discloses mutant forms of human DHFR which have increased resistance to inhibition by antifolates used in therapy including MTX. The specific mutants disclosed differ from wild-type human DHFR as a result of a single mutation occurring at amino acid 15, 31 or 34. Mutations at amino acid 22 of human DHFR have also been shown to reduce the sensitivity of the enzyme to antifolate inhibition. Ercikan et al., in Chemistry and Biology of Pteridines and Folates, J. E. Ayling, ed., Plenum Press (1993). In these mutants, the amino acids isoleucine, methionine, phenylalanine and tyrosine are substituted for the leucine of the wild-type enzyme. A particular mutant form of human DHFR encoded by the cDNA differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 in the wild-type sequence and a mutation at the amino acid corresponding to amino acid 31 in the wild-type sequence, for example Ser31Tyr22, Ser31Phe22, Gly31Tyr22, Gly31Phe22, Ala31Tyr22 and Ala31Phe22 mutants as described in International Patent Publication WO97/33988, which is incorporated herein by reference.

[0018] The cDNA molecule of the invention encodes a fusion protein that also comprises a therapeutic protein or peptide. This therapeutic protein, may be any protein or peptide which is desirably produced in a treated subject, particularly where it may be desirable to be able to control the expression levels of the therapeutic protein.

[0019] One class of proteins which may be incorporated as the therapeutic protein in the invention are protein products which can be used to enhance the toxicity of an administered drug. The genes encoding these proteins are sometimes called “suicide genes.” For example, herpes simplex virus thymidine kinase (HSV-TK) which can be used in gancyclovir (GCV) therapy to convert administered GCV into a cytotoxic derivative. HSV-TK can also convert acyclovir or 1-(2-deoxy-2-fluoro-.beta.-D-arabinofuranosyl)-5-iodouracil (FIAU) into toxic substances. Any type of HSV-TK which is effective to catalyze at least one of these conversions may be used in the present invention. By way of non-limiting example, the sequence of the gene coding for the herpes simplex virus type 1 thymidine kinase enzyme has been described in the literature (see, McKnight et al., Nucl. Acids Res. 8, 5949-5964 (1980), GenBank Accession No. J02224, Seq. ID No. 6). Natural variants of HSV-TK exist, leading to proteins having a comparable enzyme activity with respect to thymidine, or ganciclovir (M. Michael et al., 1995 Biochem. Biophys. Res. Commun 209, p. 966). Similarly, derivatives have been described which were obtained by directed mutagenesis at the binding site of the enzyme with the substrate. For example, U.S. Pat. Nos. 6,245,543 and 6,207,150, which are incorporated herein by reference describe mutant forms of HSV-TK.

[0020] Another gene of this type is the codA gene of Escherichia coli encoding cytosine deaminase which can be used for the selective elimination of unwanted human cells. (See, Austin, E. A. et al., Mol. Pharmacol. 43 (3), 380-387 (1993), GenBank Accession No. S56903, Seq. ID No. 7) Cytosine dearninase is the first enzyme of the only metabolic pathway by which exogeneous cytosine or endogeneous cytosine from pyrimidine nucleotide breakdown is utilized by way of hydrolytic deamination to uracil and ammonia. Cytosine deaminases have been found in prokaryotes and lower eukaryotes, for example, the fungi Cryptococcus neoformans, Candida albicans, Torulopsis glabrata, Sporothrix schenckii, Aspergillus, Cladosporium, and Phialophora (J. E. Bennett, Chapter 50: Antifungal Agents, in Goodman and Gilman's the Pharmacological Basis of Therapeutics 8th ed., A. G. Gilman, ed., Pergamon Press, New York, 1990) and the bacteria Escherichia coli and Salmonella typhimurium (L. Andersen, et al., Archives of Microbiology, 152; 115-118, 1989 ). In these microorganisms the genetically encoded enzyme serves the same purpose: to help provide uracil from cytosine for nucleic acid synthesis. The E. coli enzyme and gene are representative of the group. Cytosine deaminase appears to be absent in higher eukaryotes, both in mammals as well as in plants. (Koechlin et al., Biochem Phannacol. 15, 435-446 (1966)); Ross, C., Plant Physiol. 40, 65-73 (1965)). Cytosine deaminase deaminates the innocuous fluorocytosine into fluorouracil, a highly toxic compound when efficiently converted to 5-fluoro-UMP. Thus, fusion proteins in accordance with the invention containing a sequence encoding cytosine deaminase and a mammalian DHFR can be used to provide localized toxicity upon administration of 5-fluorocytosine.

[0021] Other proteins within this class include varicella zoster TK (VZV-TK) gene. VZV-TK is able to covert the pro-drugs gancyclovir, acyclovir, 1-(2-deoxy-2-fluoro-.beta.-D-arabinofuranosyl)-5-iodouracil (FIAU) and 6-methoxypurine arabinoside into toxic substances. (See, U.S. Pat. No. 5,631,236 which is incorporated herein by reference).

[0022] Another class of proteins which may be incorporated as the therapeutic protein in the invention are products of a proapoptotic gene such as Bax, apoptin and Fas. The sequence of Bax is provided for mouse at GenBanK Accession No. NM_(—) 007527 (Seq. ID No. 8), for rat at GenBank Accession No. AB046392 (Seq. ID No. 9) and for human at GenBank Accession No. AX057142 (Seq. ID No. 10). Pas Protein sequences are known from GenBank Accession No. AAC 50124 (Seq. ID No. 11). Apoptin sequences are known from GenBank Accession No. NP_(—)056774 (Seq. ID No. 12). Increased expression of these proteins under control of the DHFR part of the fusion results in killing or suppression of transfected tumor cells by sensitizing them to chemotherapeutic drugs.

[0023] The therapeutic protein may also be a product of a tumor suppressor gene. Specific tumor suppressor genes include p53, p21, p27, p16 and p14. Increased expression of these proteins under control of the DHFR part of the fusion results in killing or suppression of transfected tumor cells by sensitizing them to chemotherapeutic drugs.

[0024] The therapeutic protein may also be an immunostimulatory molecule, such as an interleukin, macrophage stimulating factors, and interferons. Specific non-limiting examples of immunostimulatory molecules include IL-2, IL-12, GMCSF. Enhanced expression of such immunostimulatory molecules boosts the immune system so that T-cell mediated cell killing is augmented.

[0025] The therapeutic protein can also be a functional proteins useful in gene therapy. For example, DHFR-beta-globin can be used to provide an inducible source of a wild-type or enhanced beta-globin protein to replace a defective protein. Similarly, where the functional protein is one that needs some measure of regulation (for example insulin in response to glucose levels), expression can be regulated by administering antifolate in response to measured levels of a metabolite (i.e., glucose in the case of insulin).

[0026] In addition to the therapeutic proteins described above, the cDNA may also encode a reporter protein, such as green fluorescent protein, to facilitate monitoring of the extent and distribution of protein expression. The sequence of enhanced green fluorsecent protein (EGFP) is known from GenBank Accession No. L29345 (Seq. ID No. 13). The combination of DHFR and a reporter protein alone has utility as a diagnostic tool.

[0027] The cDNA molecules of the invention are made using techniques conventional for preparation of cDNA molecules encoding fusion proteins. In general, this involves amplification or cloning of a cDNA sequence encoding the desired parts of the ultimate fusion protein with matched restriction sites flanking each portion. Site-specific mutatgenesis can be used to introduce mutations, and to introduce restriction sites near or at the ends of amplification products. The cDNA sequence is then assembled into a corresponding restriction site in a vector of choice, cloned and selected. In the examples below, the DHFR is placed upstream of the therapeutic protein, and this is effective to allow DHFR inhibition to control expression of the fusion, but the invention is not limited to this orientation. The cDNA may be in the form of an expression vector including promoters appropriate to the subject to be treated. For example, expression of the fusion proteins in mammalian subjects, including humans, may be achieved using either strong viral promoters or tissue specific promoters. If desired, the cDNA may include an IRES to produce separate proteins, so that function in the expressed fusion would not be an issue. It should be noted, however, that antifolate-mediated translational upregulation may not be as effective when an IRES is present, as compared to the fusion protein without the IRES.

[0028] Because the cDNA molecules of the invention encode a new class of fusion proteins in which the therapeutic protein component can be essentially anything for which it is desirable to be able to control expression levels, they can be used in for a wide variety of applications. The resulting fusion proteins also constitute an aspect of the present invention. Such fusion proteins, in accordance with the invention comprise a DHFR portion and a therapeutic protein as described above. The term “fusion protein” means that this combination of a DHFR and a therapeutic protein are an artificial construct, and not a naturally occurring protein.

[0029] The cDNA molecules of the invention can be used to treat a wide variety of cancer types, including without limitation colorectal cancer, liver cancer, pancreatic cancer, lymphomas, lung cancer, prostate cancer and breast cancer using suicide genes as the therapeutic gene.

[0030] The cDNA molecules of the invention are administered to a mammalian subject to provide enhanced delivery of the therapeutic protein. The mammalian subject may be an animal, or a human. The cDNA can be administered as naked DNA or in a carrier such as a liposome or lipid particle, or in a viral construct, e.g,. retorvirus, adenovirus etc. Administration may be by intravenous, intramuscular or subcutaneous injection. In one specific embodiment of the invention which can be used for example in treatment of liver cancer, the cDNA is administered using the hepatic artery infusion (HAI) system now in use for delivery of fluorodeoxyurideine (FuDR) in liver metastasis of colorectal cancer. Ron and Kemany, Semin. Oncol. 26(5): 524-535 (1999).

[0031] The cDNA is administered in an amount sufficient to provide expression in target cells or tissues at levels sufficient to produce a therapeutic benefit. In the case of cDNA which encodes a fusion protein containing a suicide gene such as HSV-TK, the amount administered of cDNA is suitably enough to transduce 10 to 20% or more of the target tumor cells and associated neovasculature. In the case of other types of fusion proteins, the amount of cDNA administered and the dosage schedule will depend on the desired levels of the therapeutic protein, the efficiency of expression and the stability of transduction. The appropriate level can be determined for any given fusion through routine testing.

[0032] Once the cDNA molecule has been administered, expression can be stimulated through subsequent administration of compounds such as antifolates which overcome the repression of DHFR expression and folates such as dihydrofolate. Specific non-limiting examples of appropriate antifolates include methotrexate, trimetrexate and aminopterins, such as 10 propargyl-10-deazaaminopterin. (See U.S. Pat. No. 6,028,071 which is incorporated herein by reference). The antifolate can be administered by any of the routes mentioned above for the cDNA, and is preferably administered by the same route as the cDNA in a given therapy to facilitate delivery to the same sites. The antifolate may be administered in a single or in multiple periodic bolus administrations, or as a continuous administration over a period of time. The amount administered is bounded at the upper limit by toxicity issues. For example, in the case of TMTX, the known toxicity levels indicate that an appropriate therapeutic dosage would be in the range of from 0.1 to 10 μM. Variable amounts less than toxic levels may be supplied to result in variable amounts of expression of the therapeutic protein. Leucovorin may be coadministered to reduce toxic side effects.

EXAMPLE 1

[0033] A fusion cDNA was constructed as illustrated in FIG. 1. As shown, this cDNA contains a sequence encoding a double mutant (Phe22 Ser31) of human DHFR and HSV-thymidine kinase in an SPG-based retroviral vector as described in Riviere et al., Proc. Nat'l Acad. Sci. (USA) 92: 6733-6737 (1995). The coding sequence for the double mutant DHFR was as set forth in Ercikan-Abali et al., Cancer Res. 56: 4142-445 (1996). A published coding sequences for HSV-TK (accession no. AB009258, (Seq. ID No. 14)) was used.

[0034] Retrovirus-producing cell-lines were generated by transfection of DHFR-HSV1-TK plasmid in parental GP+envAM12 cells. Transfection was performned three times at cell densities of 30%, 50% and 75% using Superfect (Qiagen, Chatsworth, Calif.) as described by the manufacturer. Clones of the retrovirus were selected in 150 nM TMTX. Viral titers were determined against NIH 3T3 cells. Retrovirus-producing AM12V cells were grown in medium without antifolate to a density of 60-80%; the day before infection, the mdeium was changed. Viral transduction was performed by infecting colon cancer cells plated 48 hours before infection in 10 cm dishes. Four single virus exporsures with the desired multiplicity of infection (moi), each of 6 hour duration, were carried out. For each single exposure, fresh AM12V supernatant was filtered through a 0.45 μm cellulose acetate filter and supplemented with polybrene (8 μg/ml). The 2-hour viral transduction was performedin 6 well plates.

[0035] The transduced cells were treated with varying amounts of TMTX (10, 100 and 1000 μM) and levels of fusion protein were detected by Western blotting using either an anti-HSV-TK antibody or an anti-human DHFR antibody. As shown in FIG. 2, upregulation of fusion protein expression was observed. These transduced cells showed increased sensitivity to GCV as compared to unselected cells or untransduced cells (FIG. 3).

EXAMPLE 2

[0036] The transduced HCT-8 cells of accumulated more ¹⁴C-FIAU than untransduced cells (where accumulation was not detectable), indicating HSV-TK activity. ³H-thymidine incorporation was comparable. (FIGS. 4 and 5) PET scanning was used for demonstration of in vivo upregulation of the fusion gene scanning. Nude rats bearing human colon tumor cells (HCT-8 and C-85) were transduced ex vivo with the SFG-DHFR/HSVTK vector (FIG. 1) and subsequently treated by intraperitoneal injeciton with either acute (50 mg/kg at 10 am and 6 pm on day before imaging) or chronic doses (10 mg/kg 3 times per week for 3 weeks before imaging (total of 9 doses)) of TMTX. A radiolabeled substrate of HSV-TK (¹²⁴I-FIAU, 2-fluoro-1β-D-arabino-furanosyl-5-iodo-uracil) was used to image tumors in vivo (250-400 μCi per animal via the penile vein). Tumors that had been transduced with the fusion cDNA vector showed increased image intensity by PET scanning as opposed to untransformed tumors. Furthermore, better anti-tumor response of transduced tumors was observed using TMTX/GCV combination therapy than using either TMTX or GMCV alone. (FIG. 6).

EXAMPLE 3

[0037] Three colorectal cancer cells lines (HCT-8, HCT-116 and a cell line, C85, recently established from a patient with liver metastasis) were transduced with the SFG-DHFR/HSV-TK fusion vector of Example 1. Transduction was verified by PCR using transgene specific primers and elevation of DHFR-HSVTK mRNA and protein expression. After treatment of the transduced cells with several cycles of nine day exposures to increasing concentration of TMTX, a stable increase in mRNA and protein levels of the fusion protein was seen. Furthermore, these cells exhibits a 250-fold increase in sensitivity to GCV and significantly increased accumulation of ¹⁴C-FIAU as compared to non-transduced cells. A transient increase in fusion protein levels without an increase in mRNA was observed following treatment of the cells with high concentrations (1000 μM) of TMTX, methotrexate or dihydrofolate.

[0038] FIGS. 7A-D show GCV sensitivty and TMTX resisatnce in parental, tranduced and TMTX exposed colon cancer cells of the HCT-116 and HCT-8 cells lines. Bulk transduction of HCT-116 and HCT-8 was carried out with an moi of 30 for 24 hours or an moi of 2.5 for 2 hours to produce cell lines 116HT and 116LT, and 8HT and 8LT, respectively. Successful gene transfer and transgene expression was confirmed by PCR and Western blotting. The percentage of infected cells was determined by colony formation assay using the GCV sensitivity of DHFR-HSV1-TK-expressing cells to be as follows: 116HT, very high (no colony formation); 116LT, 80%; 8HT, 53%. Infection of 8LT was not detectable with the assay used.

[0039] GCV amd TMTX cytotoxicities were measured on the transduced cells. 116LT cells exhibited a moderate and 116HT a higher GCV and TMTX resistance as compared with parental cell lines. (FIGS. 7A and C). This finding correlates with observed levels of fusion protein expression in these cells. In a similar way, detected fusion protein expression correlates with the drug cytotoxicity in transduced HCT-8 cells: 8HT cells, but not in 8LT cells showed GCV sensitivity and TMTX resistance ((FIGS. 7B and D).

[0040] When HCT-8 cells were treated chronically with increasing concentrations of TMTX, a 250-fold increase in GCV sensitivity was measured (FIG. 7B, line 8LT-CT), accompanied by an increased gene copy number and fusion protein expression. This induction of expression of the DHFR-HSV1 TK fusion protein was shown to be dose-dependent with both MTX and TMTX over concentrations ranges of 10⁻² to 1 μM. Induction was also observed with the DHFR substrate, dihydrofolate, at a concentration of 50 μM. In contrast, treatment of cells with etoposide, a topoisimerase II inhibitor, did not cause induction of the fusion protein.

EXAMPLE 4

[0041] Rats bearing flank tumors were treated with 10 mg/kg of TMTX for three days (once daily), or with a single high dose of 100 mg/kg. The levels of DHFR-HSV1 TK fusion protein in the tumor tissue of antifolate treated rats, as well as in water-treated controls were analyzed. All antifolate treated animals showed elevated levels of the fusion protein, ranging from 1.5 to 4-fold relative to the controls. The mean increase was at least 2-fold.

[0042] In a second set of experiments, tumors derived from 8LT-CT and parental HCT-8 cells were evaluated by in vivo imaging. Before the imaging, each animal received three cycles of 10 mg/kg of TMTX, three times daily for three days per cycle. Using PET and the tracer ¹²⁴I-FIAUan increase in tumor-signal intensity in TMTX-treated rats was observed. Measurements of ¹²⁴I-FIAU uptake (% dose per g) from 7 treated and 7 control rats showed a 2.6 fold-higher ¹²⁴I- FIAU accumulation in transduced tumor tissue following TMTX treatment as compared with untreated controls.

EXAMPLE 5

[0043] SFG-based retroviral vectors were prepared encoding EGFP, DHFR-EFGP and DHFR and EGFP separated by an IRES and shown in FIG. 8. The sequence for EGFP is known from published sequences (accession no. for cloning vector pEGFP-1 is U55761, (Seq. ID No. 15)) The procedures for introduction of the IRES were as described in Frebourg et al., Cancer Res. 54: 876-881 (1994).

[0044] Transfections of parental GP+envAM12 cells (Markowitz et al., Virology 167:400-405 (1988)) with EGFP-containing SFG-plasmids was carried out using DOTAP transfecting reagent (N-{1-(2,3-dioleyloxy)propyl]-N,N,N,-trimethylammonium methyl sulfate, Roche Molecular Biochemicals). Cells transfected with EGFP-expressing vectors were cultrued for at least 12 days and subsequently sorted for EGFP-positive cells using an FACS Vantage SE cell sorter (Becton Dickinson). For fluorescence microscopy, these cells were grown in T25 flasks. Confluent cells were cultured in fresh media with or without TMTX. Fluorescent images of randomly selected areas of the monolayer were taken with a Zeiss Axlovert S100 microscope.

[0045] In cells transfected with the DHFR-EGFP fusion vector, cellular expression of the fusion protein was observed. This expression was increased upon treatment with 1 μM of TMTX, and this increase was durable at 24 and 48 hours after treatrment. Cells transfected with plasmids expressing DHFR and EGFP separated by an IRES, or just EGFP both resulted in expression of EGFP at higher levels than cells transfected with DHFR-EGFP fusion vectors, but this was not increased by the addition of TMTX.

1 15 1 564 DNA Canis familiaris 1 atggtgcgca cgctgaactg catcgtcgcc gtgtcccaga acatgggcat cggcaggaac 60 ggggacctgc cctggccccc gctcaggaat gaattcaagt atttccaaag aatgaccacg 120 aactcctccg tggcaaggta aacagaattt ggtgattatg ggtaggaaga catggttctc 180 tattcttgag aagaatcgac cgttaaagga cagaattaat atagttctca gcagagacct 240 caaggaacct ccacaaggag ctcattttct tgccaaaagt cggatgatgc tttaaaactt 300 actgagcaac cagaattagc aaataaagtg gacatggttt ggatagtggg aggcagttct 360 gtttataagg aagccatgaa caaaccaggc catcttagac tatttgtgac aaggattatg 420 catgaatttg aaagtgacac gtttttccca gaaattgatt tggagaaata taaacttctg 480 ccagaatacc caggtgtgct ttctgatgtc caggaggaga aaggcattaa gtacaaattt 540 gaagtatatg agaagaacga ttaa 564 2 188 PRT monkey 2 Met Asp Ile Ala Val Asn Cys Ile Val Ala Val Asp Glu Gln Leu Gly 1 5 10 15 Ile Gly Lys Asn Gly Thr Met Pro Trp Pro Tyr Leu Arg Asn Glu Met 20 25 30 Met Tyr Phe Gln Lys Met Thr Ser Thr Pro Ser Val Val Gly Glu Lys 35 40 45 Asn Val Val Ile Met Gly Lys Arg Thr Trp Phe Ser Ile Pro Glu Lys 50 55 60 Lys Arg Pro Leu Val Asn Arg Ile Asn Ile Ile Leu Ser Arg Glu Leu 65 70 75 80 Arg Glu Pro Pro His Gly Ala His Phe Leu Ala Arg Thr Leu Asp Asp 85 90 95 Ala Phe Asn Phe Tyr Arg Gln Tyr Lys Leu Lys Glu Gln Leu Asn Thr 100 105 110 Val Trp Val Ile Gly Gly Lys Ser Val Tyr Glu Ser Val Leu Asn Tyr 115 120 125 Lys Cys Pro Leu Lys Leu Tyr Ile Thr Arg Ile Met Glu Phe Ser Asp 130 135 140 Cys Asp Val Phe Phe Pro Ser Ile Asn Phe Thr Glu Tyr Leu Met Leu 145 150 155 160 Ser Glu Leu Pro Gly Lys Asp Thr Asn Phe Glu Glu Asn Gly Ile Lys 165 170 175 Tyr Lys Phe Gln Val Tyr Glu Lys Asn Phe Asn Lys 180 185 3 187 PRT rat 3 Met Val Arg Pro Leu Asn Cys Ile Val Ala Val Ser Gln Asn Met Gly 1 5 10 15 Ile Gly Lys Asn Gly Leu Asp Pro Trp Pro Leu Leu Arg Asn Glu Phe 20 25 30 Lys Tyr Phe Gln Arg Met Thr Thr Thr Ser Ser Val Glu Gly Lys Gln 35 40 45 Asn Leu Val Ile Met Gly Arg Lys Thr Trp Phe Ser Ile Pro Glu Lys 50 55 60 Asn Arg Pro Leu Lys Asp Arg Ile Asn Ile Val Leu Ser Arg Glu Leu 65 70 75 80 Lys Glu Pro Pro Gln Gly Ala His Phe Leu Ala Lys Ser Leu Asp Asp 85 90 95 Ala Leu Lys Leu Ile Glu Gln Pro Glu Leu Ala Ser Lys Val Asp Met 100 105 110 Val Trp Val Val Gly Gly Ser Ser Val Tyr Gln Glu Ala Met Asn Gln 115 120 125 Pro Gly His Leu Arg Leu Phe Val Thr Arg Ile Met Gln Glu Phe Glu 130 135 140 Ser Asp Thr Phe Phe Pro Glu Ile Asp Leu Glu Lys Tyr Lys Leu Leu 145 150 155 160 Pro Glu Tyr Pro Gly Val Leu Ser Glu Ile Gln Glu Glu Lys Gly Ile 165 170 175 Lys Tyr Lys Phe Glu Val Tyr Glu Lys Lys Asp 180 185 4 187 PRT mouse 4 Met Val Arg Pro Leu Asn Cys Ile Val Ala Val Ser Gln Asn Met Gly 1 5 10 15 Ile Gly Lys Asn Gly Leu Asp Pro Trp Pro Pro Leu Arg Asn Glu Phe 20 25 30 Lys Tyr Phe Gln Arg Met Thr Thr Thr Ser Ser Val Glu Gly Lys Gln 35 40 45 Asn Leu Val Ile Met Gly Arg Lys Thr Trp Phe Ser Ile Pro Glu Lys 50 55 60 Asn Arg Pro Leu Lys Asp Arg Ile Asn Ile Val Leu Ser Arg Glu Leu 65 70 75 80 Lys Glu Pro Pro Arg Gly Ala His Phe Leu Ala Lys Ser Leu Asp Asp 85 90 95 Ala Leu Arg Leu Ile Glu Gln Pro Glu Leu Ala Ser Lys Val Asp Met 100 105 110 Val Trp Ile Val Gly Gly Ser Ser Val Tyr Gln Glu Ala Met Asn Gln 115 120 125 Pro Gly His Leu Arg Leu Phe Val Thr Arg Ile Met Gln Glu Phe Glu 130 135 140 Ser Asp Thr Phe Phe Pro Glu Ile Asp Leu Gly Lys Tyr Lys Leu Leu 145 150 155 160 Pro Glu Tyr Pro Gly Val Leu Ser Glu Val Gln Glu Glu Lys Gly Ile 165 170 175 Lys Tyr Lys Phe Glu Val Tyr Glu Lys Lys Asp 180 185 5 186 PRT human 5 Val Gly Ser Leu Asn Cys Ile Val Ala Val Ser Gln Asn Met Gly Ile 1 5 10 15 Gly Lys Asn Gly Asp Leu Pro Trp Pro Phe Leu Arg Asn Glu Phe Arg 20 25 30 Tyr Phe Gln Arg Met Thr Thr Thr Ser Ser Val Glu Gly Lys Gln Asn 35 40 45 Leu Val Ile Met Gly Lys Lys Thr Trp Phe Ser Ile Pro Glu Lys Asn 50 55 60 Arg Pro Leu Lys Gly Arg Ile Asn Leu Val Leu Ser Arg Glu Leu Lys 65 70 75 80 Glu Pro Pro Gln Gly Ala His Phe Leu Ser Arg Ser Leu Asp Asp Ala 85 90 95 Leu Lys Leu Thr Glu Gln Pro Glu Leu Ala Asn Lys Val Asp Met Val 100 105 110 Trp Ile Val Gly Gly Ser Ser Val Tyr Lys Glu Ala Met Asn His Pro 115 120 125 Gly His Leu Lys Leu Phe Val Thr Arg Ile Met Gln Asp Phe Glu Ser 130 135 140 Asp Thr Phe Phe Pro Glu Ile Asp Leu Glu Lys Tyr Lys Leu Leu Pro 145 150 155 160 Glu Tyr Pro Gly Val Leu Ser Asp Val Gln Glu Glu Lys Gly Ile Lys 165 170 175 Tyr Lys Phe Glu Val Tyr Glu Lys Asn Asp 180 185 6 376 PRT herpes simplex virus 6 Met Ala Ser Tyr Pro Cys His Gln His Ala Ser Ala Phe Asp Gln Ala 1 5 10 15 Ala Arg Ser Arg Gly His Ser Asn Arg Arg Thr Ala Leu Arg Pro Arg 20 25 30 Arg Gln Gln Glu Ala Thr Glu Val Arg Leu Glu Gln Lys Met Pro Thr 35 40 45 Leu Leu Arg Val Tyr Ile Asp Gly Pro His Gly Met Gly Lys Thr Thr 50 55 60 Thr Thr Gln Leu Leu Val Ala Leu Gly Ser Arg Asp Asp Ile Val Tyr 65 70 75 80 Val Pro Glu Pro Met Thr Tyr Trp Gln Val Leu Gly Ala Ser Glu Thr 85 90 95 Ile Ala Asn Ile Tyr Thr Thr Gln His Arg Leu Asp Gln Gly Glu Ile 100 105 110 Ser Ala Gly Asp Ala Ala Val Val Met Thr Ser Ala Gln Ile Thr Met 115 120 125 Gly Met Pro Tyr Ala Val Thr Asp Ala Val Leu Ala Pro His Val Gly 130 135 140 Gly Glu Ala Gly Ser Ser His Ala Pro Pro Pro Ala Leu Thr Leu Ile 145 150 155 160 Phe Asp Arg His Pro Ile Ala Ala Leu Leu Cys Tyr Pro Ala Ala Arg 165 170 175 Tyr Leu Met Gly Ser Met Thr Pro Gln Ala Val Leu Ala Phe Val Ala 180 185 190 Leu Ile Pro Pro Thr Leu Pro Gly Thr Asn Ile Val Leu Gly Ala Leu 195 200 205 Pro Glu Asp Arg His Ile Asp Arg Leu Ala Lys Arg Gln Arg Pro Gly 210 215 220 Glu Arg Leu Asp Leu Ala Met Leu Ala Ala Ile Arg Arg Val Tyr Gly 225 230 235 240 Leu Leu Ala Asn Thr Val Arg Tyr Leu Gln Gly Gly Gly Ser Trp Trp 245 250 255 Glu Asp Trp Gly Gln Leu Ser Gly Thr Ala Val Pro Pro Gln Gly Ala 260 265 270 Glu Pro Gln Ser Asn Ala Gly Pro Arg Pro His Ile Gly Asp Thr Leu 275 280 285 Phe Thr Leu Phe Arg Ala Pro Glu Leu Leu Ala Pro Asn Gly Asp Leu 290 295 300 Tyr Asn Val Phe Ala Trp Ala Leu Asp Val Leu Ala Lys Arg Leu Arg 305 310 315 320 Pro Met His Val Phe Ile Leu Asp Tyr Asp Gln Ser Pro Ala Gly Cys 325 330 335 Arg Asp Ala Leu Leu Gln Leu Thr Ser Gly Met Val Gln Thr His Val 340 345 350 Thr Thr Pro Gly Ser Ile Pro Thr Ile Cys Asp Leu Ala Arg Thr Phe 355 360 365 Ala Arg Glu Met Gly Glu Ala Asn 370 375 7 427 PRT Escherichia coli 7 Met Ser Asn Asn Ala Leu Gln Thr Ile Ile Asn Ala Arg Leu Pro Gly 1 5 10 15 Glu Glu Gly Leu Trp Gln Ile His Leu Gln Asp Gly Lys Ile Ser Ala 20 25 30 Ile Asp Ala Gln Ser Gly Val Met Pro Ile Thr Glu Asn Ser Leu Asp 35 40 45 Ala Glu Gln Gly Leu Val Ile Pro Pro Phe Val Glu Pro His Ile His 50 55 60 Leu Asp Thr Thr Gln Thr Ala Gly Gln Pro Asn Trp Asn Gln Ser Gly 65 70 75 80 Thr Leu Phe Glu Gly Ile Glu Arg Trp Ala Glu Arg Lys Ala Leu Leu 85 90 95 Thr His Asp Asp Val Lys Gln Arg Ala Trp Gln Thr Leu Lys Trp Gln 100 105 110 Ile Ala Asn Gly Ile Gln His Val Arg Thr His Val Asp Val Ser Asp 115 120 125 Ala Thr Leu Thr Ala Leu Lys Ala Met Leu Glu Val Lys Gln Glu Val 130 135 140 Ala Pro Trp Ile Asp Leu Gln Ile Val Ala Phe Pro Gln Glu Gly Ile 145 150 155 160 Leu Ser Tyr Pro Asn Gly Glu Ala Leu Leu Glu Glu Ala Leu Arg Leu 165 170 175 Gly Ala Asp Val Val Gly Ala Ile Pro His Phe Glu Phe Thr Arg Glu 180 185 190 Tyr Gly Val Glu Ser Leu His Lys Thr Phe Ala Leu Ala Gln Lys Tyr 195 200 205 Asp Arg Leu Ile Asp Val His Cys Asp Glu Ile Asp Asp Glu Gln Ser 210 215 220 Arg Phe Val Glu Thr Val Ala Ala Leu Ala His His Glu Gly Met Gly 225 230 235 240 Ala Arg Val Thr Ala Ser His Thr Thr Ala Met His Ser Tyr Asn Gly 245 250 255 Ala Tyr Thr Ser Arg Leu Phe Arg Leu Leu Lys Met Ser Gly Ile Asn 260 265 270 Phe Val Ala Asn Pro Leu Val Asn Ile His Leu Gln Gly Arg Phe Asp 275 280 285 Thr Tyr Pro Lys Arg Arg Gly Ile Thr Arg Val Lys Glu Met Leu Glu 290 295 300 Ser Gly Ile Asn Val Cys Phe Gly His Asp Asp Val Phe Asp Pro Trp 305 310 315 320 Tyr Pro Leu Gly Thr Ala Asn Met Leu Gln Val Leu His Met Gly Leu 325 330 335 His Val Cys Gln Leu Met Gly Tyr Gly Gln Ile Asn Asp Gly Leu Asn 340 345 350 Leu Ile Thr His His Ser Ala Arg Thr Leu Asn Leu Gln Asp Tyr Gly 355 360 365 Ile Ala Ala Gly Asn Ser Ala Asn Leu Ile Ile Leu Pro Ala Glu Asn 370 375 380 Gly Phe Asp Ala Leu Arg Arg Gln Val Pro Val Arg Tyr Ser Val Arg 385 390 395 400 Gly Gly Lys Val Ile Ala Ser Thr Gln Pro Ala Gln Thr Thr Val Tyr 405 410 415 Leu Glu Gln Pro Glu Ala Ile Asp Tyr Lys Arg 420 425 8 192 PRT mouse 8 Met Asp Gly Ser Gly Glu Gln Leu Gly Ser Gly Gly Pro Thr Ser Ser 1 5 10 15 Glu Gln Ile Met Lys Thr Gly Ala Phe Leu Leu Gln Gly Phe Ile Gln 20 25 30 Asp Arg Ala Gly Arg Met Ala Gly Glu Thr Pro Glu Leu Thr Leu Glu 35 40 45 Gln Pro Pro Gln Asp Ala Ser Thr Lys Lys Leu Ser Glu Cys Leu Arg 50 55 60 Arg Ile Gly Asp Glu Leu Asp Ser Asn Met Glu Leu Gln Arg Met Ile 65 70 75 80 Ala Asp Val Asp Thr Asp Ser Pro Arg Glu Val Phe Phe Arg Val Ala 85 90 95 Ala Asp Met Phe Ala Asp Gly Asn Phe Asn Trp Gly Arg Val Val Ala 100 105 110 Leu Phe Tyr Phe Ala Ser Lys Leu Val Leu Lys Ala Leu Cys Thr Lys 115 120 125 Val Pro Glu Leu Ile Arg Thr Ile Met Gly Trp Thr Leu Asp Phe Leu 130 135 140 Arg Glu Arg Leu Leu Val Trp Ile Gln Asp Gln Gly Gly Trp Glu Gly 145 150 155 160 Leu Leu Ser Tyr Phe Gly Thr Pro Thr Trp Gln Thr Val Thr Ile Phe 165 170 175 Val Ala Gly Val Leu Thr Ala Ser Leu Thr Ile Trp Lys Lys Met Gly 180 185 190 9 1954 DNA rat 9 aaaaaaaaaa aagatacaaa tagttaaaga cagaaagaag agctgccctc ggtggcacac 60 acctttactc cctgcacagg agcagaggca gcagatggca gatctctatg ttccaggcca 120 gcttggtcta cagactgaga tccaggagag ccagggctac acagagaagc tatttcaaat 180 aacaaacaaa cactcagggt gctttcaggg cttttcaaca gaggactcaa gccaagagac 240 tttctgactc ccagaaactc tactcttccc tgctcaacac ttcccccggt cttaggtctc 300 agccaccctc agaagactca tagactccta ctagaatatt ccagaatctg tcctgacctg 360 ctgctacttc acattgtccc tctttcttct cttcttcttt tctcctcctc cttctcttcc 420 tattcttttt tccttccttc cttccttcct tccttccttc cttccttcct tccttccttc 480 cttccttcct tccttccttt gagacagggt ttctctaagt agccatggct gtcgtggatc 540 tggctttgta gtccagattg cccttaaact cagagatcta ccttcctgca tcctgagagc 600 tgggattaaa agtgtacaca actaccaccc gactcttctc ctcctcctcc tcctcctttt 660 cttgaggcta aaggtctctc ttggtatcct atgctggctt catagggctt ccatgttccg 720 ggattacagg tatgggccac aataccaggg tctccttgct cctctcatct tcctctttgt 780 tttatgcttt gagtgatggt ctcagtatct agtgtaattg acctgtctct tgctatgtag 840 acttgttgtg ttttataaaa aagaaataga ggcaggatat gttttggtag aacatggtat 900 ggtgaggtgg gaggggtgcc ccggcaggcc catactgaat ccccctgaag taccagccat 960 gtagtatgta gtgccagatg tagtaccacg tagtgccaaa tgtagtatgg aatagagttt 1020 atttagggca tgggaagtgg agttgggaag ggaggagggg ggaaggggag agaaaaggag 1080 gggagaggag atggccagga actcatggaa tgggctggag gggtgcgggg aagaaggggc 1140 agaaagtaag aggataagag agtatgagag cttggacagg gcagatagcc ccttttatag 1200 taggtcaggc atacttgtct gttgccaggt aactgtgtgt gtgtggggga gactagaagg 1260 aatgctaaat agcctgggtt gatcttaatt tcagagacat ctgcttgttt gtagctctga 1320 aggctggtat taaaagacat tggagccacc acacacagcc tgtttttgtt ttttgaaata 1380 gtttcttagt agtgcagctt ggactcaaac tatgcaatcc aggcttgcct caaactcctt 1440 agcaatcttc ttgcttcact ctatcagacc tatggaccat cactctggtc aagtgttttg 1500 ttttgttatg ttttttttcc agattggggc aatctcgcta cagtcctggc tggctttgag 1560 tttgtggcag gcaatattcc gtcctgcctc agtctcccaa tgctgggatg agaagcatat 1620 cctaggcagg ctttgaactt gcggcaattc tgctctaacc tccttagtac tctctaccat 1680 gaatctaatg aaggagaaat aatagaaaac aaaaacaaaa acaaaaacaa aaaaccaacc 1740 ctgggaacca gtccaggttc gggtagcgcc gcgcatgcgt gaatttaatg gcagaggccc 1800 cgccccgaaa gcgcgcgacg atcacgtgac tagttctgcg gggcggaggc catgttgcgg 1860 ggcacccacg tgagggccgc acgtctgcgg ggagtcacgt gaccggggcg cgccgcagcc 1920 gccggggcgc acccggcgag aggcagcggc agtg 1954 10 192 PRT human 10 Met Asp Gly Ser Gly Glu Gln Pro Arg Gly Gly Gly Pro Thr Ser Ser 1 5 10 15 Glu Gln Ile Met Lys Thr Gly Ala Leu Leu Leu Gln Gly Phe Ile Gln 20 25 30 Asp Arg Ala Gly Arg Met Gly Gly Glu Ala Pro Glu Leu Ala Leu Asp 35 40 45 Pro Val Pro Gln Asp Ala Ser Thr Lys Lys Leu Ser Glu Cys Leu Lys 50 55 60 Arg Ile Gly Asp Glu Leu Asp Ser Asn Met Glu Leu Gln Arg Met Ile 65 70 75 80 Ala Ala Val Asp Thr Asp Ser Pro Arg Glu Val Phe Phe Arg Val Ala 85 90 95 Ala Asp Met Phe Ser Asp Gly Asn Phe Asn Trp Gly Arg Val Val Ala 100 105 110 Leu Phe Tyr Phe Ala Ser Lys Leu Val Leu Lys Ala Leu Cys Thr Lys 115 120 125 Val Pro Glu Leu Ile Arg Thr Ile Met Gly Trp Thr Leu Asp Phe Leu 130 135 140 Arg Glu Arg Leu Leu Gly Trp Ile Gln Asp Gln Gly Gly Trp Asp Gly 145 150 155 160 Leu Leu Ser Tyr Phe Gly Thr Pro Thr Trp Gln Thr Val Thr Ile Phe 165 170 175 Val Ala Gly Val Leu Thr Ala Ser Leu Thr Ile Trp Lys Lys Met Gly 180 185 190 11 281 PRT human 11 Met Gln Gln Pro Phe Asn Tyr Pro Tyr Pro Gln Ile Tyr Trp Val Asp 1 5 10 15 Ser Ser Ala Ser Ser Pro Trp Ala Pro Pro Gly Thr Val Leu Pro Cys 20 25 30 Pro Thr Ser Val Pro Arg Arg Pro Gly Gln Arg Arg Pro Pro Pro Pro 35 40 45 Pro Pro Pro Pro Pro Leu Pro Pro Pro Pro Pro Pro Pro Pro Leu Pro 50 55 60 Pro Leu Pro Leu Pro Pro Leu Lys Lys Arg Gly Asn His Ser Thr Gly 65 70 75 80 Leu Cys Leu Leu Val Met Phe Phe Met Val Leu Val Ala Leu Val Gly 85 90 95 Leu Gly Leu Gly Met Phe Gln Leu Phe His Leu Gln Lys Glu Leu Ala 100 105 110 Glu Leu Arg Glu Ser Thr Ser Gln Met His Thr Ala Ser Ser Leu Glu 115 120 125 Lys Gln Ile Gly His Pro Ser Pro Pro Pro Glu Lys Lys Glu Leu Arg 130 135 140 Lys Val Ala His Leu Thr Gly Lys Ser Asn Ser Arg Ser Met Pro Leu 145 150 155 160 Glu Trp Glu Asp Thr Tyr Gly Ile Val Leu Leu Ser Gly Val Lys Tyr 165 170 175 Lys Lys Gly Gly Leu Val Ile Asn Glu Thr Gly Leu Tyr Phe Val Tyr 180 185 190 Ser Lys Val Tyr Phe Arg Gly Gln Ser Cys Asn Asn Leu Pro Leu Ser 195 200 205 His Lys Val Tyr Met Arg Asn Ser Lys Tyr Pro Gln Asp Leu Val Met 210 215 220 Met Glu Gly Lys Met Met Ser Tyr Cys Thr Thr Gly Gln Met Trp Ala 225 230 235 240 Arg Ser Ser Tyr Leu Gly Ala Val Phe Asn Leu Thr Ser Ala Asp His 245 250 255 Leu Tyr Val Asn Val Ser Glu Leu Ser Leu Val Asn Phe Glu Glu Ser 260 265 270 Gln Thr Phe Phe Gly Leu Tyr Lys Leu 275 280 12 281 PRT chicken anemia virus 12 Met Gln Gln Pro Phe Asn Tyr Pro Tyr Pro Gln Ile Tyr Trp Val Asp 1 5 10 15 Ser Ser Ala Ser Ser Pro Trp Ala Pro Pro Gly Thr Val Leu Pro Cys 20 25 30 Pro Thr Ser Val Pro Arg Arg Pro Gly Gln Arg Arg Pro Pro Pro Pro 35 40 45 Pro Pro Pro Pro Pro Leu Pro Pro Pro Pro Pro Pro Pro Pro Leu Pro 50 55 60 Pro Leu Pro Leu Pro Pro Leu Lys Lys Arg Gly Asn His Ser Thr Gly 65 70 75 80 Leu Cys Leu Leu Val Met Phe Phe Met Val Leu Val Ala Leu Val Gly 85 90 95 Leu Gly Leu Gly Met Phe Gln Leu Phe His Leu Gln Lys Glu Leu Ala 100 105 110 Glu Leu Arg Glu Ser Thr Ser Gln Met His Thr Ala Ser Ser Leu Glu 115 120 125 Lys Gln Ile Gly His Pro Ser Pro Pro Pro Glu Lys Lys Glu Leu Arg 130 135 140 Lys Val Ala His Leu Thr Gly Lys Ser Asn Ser Arg Ser Met Pro Leu 145 150 155 160 Glu Trp Glu Asp Thr Tyr Gly Ile Val Leu Leu Ser Gly Val Lys Tyr 165 170 175 Lys Lys Gly Gly Leu Val Ile Asn Glu Thr Gly Leu Tyr Phe Val Tyr 180 185 190 Ser Lys Val Tyr Phe Arg Gly Gln Ser Cys Asn Asn Leu Pro Leu Ser 195 200 205 His Lys Val Tyr Met Arg Asn Ser Lys Tyr Pro Gln Asp Leu Val Met 210 215 220 Met Glu Gly Lys Met Met Ser Tyr Cys Thr Thr Gly Gln Met Trp Ala 225 230 235 240 Arg Ser Ser Tyr Leu Gly Ala Val Phe Asn Leu Thr Ser Ala Asp His 245 250 255 Leu Tyr Val Asn Val Ser Glu Leu Ser Leu Val Asn Phe Glu Glu Ser 260 265 270 Gln Thr Phe Phe Gly Leu Tyr Lys Leu 275 280 13 237 PRT Aequorea victoria 13 Ser Lys Gly Glu Glu Leu Phe Thr Gly Val Val Pro Ile Leu Val Glu 1 5 10 15 Leu Asp Gly Asp Val Asn Gly Gln Lys Phe Ser Val Ser Gly Glu Gly 20 25 30 Glu Gly Asp Ala Thr Tyr Gly Lys Leu Thr Leu Lys Phe Ile Cys Thr 35 40 45 Thr Gly Lys Leu Pro Val Pro Trp Pro Thr Leu Val Thr Thr Phe Ser 50 55 60 Tyr Gly Val Gln Cys Phe Ser Arg Tyr Pro Asp His Met Lys Gln His 65 70 75 80 Asp Phe Phe Lys Ser Ala Met Pro Glu Gly Tyr Val Gln Glu Arg Thr 85 90 95 Ile Phe Tyr Lys Asp Asp Gly Asn Tyr Lys Thr Arg Ala Glu Val Lys 100 105 110 Phe Glu Gly Asp Thr Leu Val Asn Arg Ile Glu Leu Lys Gly Ile Asp 115 120 125 Phe Lys Glu Asp Gly Asn Ile Leu Gly His Lys Met Glu Tyr Asn Tyr 130 135 140 Asn Ser His Asn Val Tyr Ile Met Ala Asp Lys Pro Lys Asn Gly Ile 145 150 155 160 Lys Val Asn Phe Lys Ile Arg His Asn Ile Lys Asp Gly Ser Val Gln 165 170 175 Leu Ala Asp His Tyr Gln Gln Asn Thr Pro Ile Gly Asp Gly Pro Val 180 185 190 Leu Leu Pro Asp Asn His Tyr Leu Ser Thr Gln Ser Ala Leu Ser Lys 195 200 205 Asp Pro Asn Glu Lys Arg Asp His Met Ile Leu Leu Glu Phe Val Thr 210 215 220 Ala Ala Gly Ile Thr His Gly Met Asp Glu Leu Tyr Lys 225 230 235 14 376 PRT herpes virus 14 Met Ala Ser Tyr Pro Cys His Gln His Ala Ser Ala Phe Asp Gln Ala 1 5 10 15 Ala Arg Ser Arg Gly His Ser Asn Arg Arg Thr Ala Leu Arg Pro Arg 20 25 30 Arg Gln Gln Glu Ala Thr Glu Val Arg Leu Glu Gln Lys Met Pro Thr 35 40 45 Leu Leu Arg Val Tyr Ile Asp Gly Pro His Gly Met Gly Lys Thr Thr 50 55 60 Thr Thr Gln Leu Leu Val Ala Leu Gly Ser Arg Asp Asp Ile Val Tyr 65 70 75 80 Val Pro Asp Pro Met Thr Tyr Trp Gln Val Leu Gly Ala Ser Glu Thr 85 90 95 Ile Ala Asn Ile Tyr Thr Thr Gln His Arg Leu Asp Gln Gly Glu Ile 100 105 110 Ser Ala Gly Asp Ala Ala Val Val Met Thr Ser Ala Gln Ile Thr Met 115 120 125 Gly Met Pro Tyr Ala Val Thr Asp Ala Val Leu Ala Pro His Ile Gly 130 135 140 Gly Glu Ala Gly Ser Ser His Ala Pro Pro Pro Ala Leu Thr Leu Ile 145 150 155 160 Phe Asp Arg His Pro Ile Ala Ala Leu Leu Cys Tyr Pro Ala Ala Arg 165 170 175 Tyr Leu Met Gly Ser Met Thr Pro Gln Ala Val Leu Ala Phe Val Ala 180 185 190 Leu Ile Pro Pro Thr Leu Pro Gly Thr Asn Ile Val Leu Gly Ala Leu 195 200 205 Pro Glu Asp Arg His Ile Asp Arg Leu Ala Lys Arg Gln Arg Pro Gly 210 215 220 Glu Arg Leu Asp Leu Ala Met Leu Ala Ala Ile Arg Arg Val Tyr Gly 225 230 235 240 Leu Leu Ala Asn Thr Val Arg Tyr Leu Gln Gly Gly Gly Ser Trp Arg 245 250 255 Glu Asp Trp Gly Gln Leu Ser Gly Thr Ala Val Pro Pro Gln Gly Ala 260 265 270 Glu Pro Gln Ser Asn Ala Gly Pro Arg Pro His Ile Gly Asp Thr Leu 275 280 285 Phe Thr Leu Phe Arg Ala Pro Glu Leu Leu Ala Pro Asn Gly Asp Leu 290 295 300 Tyr Asn Val Phe Ala Trp Ala Leu Asp Val Leu Ala Lys Arg Leu Arg 305 310 315 320 Pro Met His Val Phe Ile Leu Asp Tyr Asp Gln Ser Pro Ala Gly Cys 325 330 335 Arg Asp Ala Leu Leu Gln Leu Thr Ser Gly Met Val Gln Thr His Val 340 345 350 Thr Thr Pro Gly Ser Ile Pro Thr Ile Cys Asp Leu Ala Arg Thr Phe 355 360 365 Ala Arg Glu Met Gly Glu Ala Asn 370 375 15 4151 DNA Artificial Cloning vector pEGFP-1, complete sequence, enhanced green fluorescent protein (egfp) and neomycin phosphotransferase genes 15 tagttattac tagcgctacc ggactcagat ctcgagctca agcttcgaat tctgcagtcg 60 acggtaccgc gggcccggga tccaccggtc gccaccatgg tgagcaaggg cgaggagctg 120 ttcaccgggg tggtgcccat cctggtcgag ctggacggcg acgtaaacgg ccacaagttc 180 agcgtgtccg gcgagggcga gggcgatgcc acctacggca agctgaccct gaagttcatc 240 tgcaccaccg gcaagctgcc cgtgccctgg cccaccctcg tgaccaccct gacctacggc 300 gtgcagtgct tcagccgcta ccccgaccac atgaagcagc acgacttctt caagtccgcc 360 atgcccgaag gctacgtcca ggagcgcacc atcttcttca aggacgacgg caactacaag 420 acccgcgccg aggtgaagtt cgagggcgac accctggtga accgcatcga gctgaagggc 480 atcgacttca aggaggacgg caacatcctg gggcacaagc tggagtacaa ctacaacagc 540 cacaacgtct atatcatggc cgacaagcag aagaacggca tcaaggtgaa cttcaagatc 600 cgccacaaca tcgaggacgg cagcgtgcag ctcgccgacc actaccagca gaacaccccc 660 atcggcgacg gccccgtgct gctgcccgac aaccactacc tgagcaccca gtccgccctg 720 agcaaagacc ccaacgagaa gcgcgatcac atggtcctgc tggagttcgt gaccgccgcc 780 gggatcactc tcggcatgga cgagctgtac aagtaaagcg gccgcgactc tagatcataa 840 tcagccatac cacatttgta gaggttttac ttgctttaaa aaacctccca cacctccccc 900 tgaacctgaa acataaaatg aatgcaattg ttgttgttaa cttgtttatt gcagcttata 960 atggttacaa ataaagcaat agcatcacaa atttcacaaa taaagcattt ttttcactgc 1020 attctagttg tggtttgtcc aaactcatca atgtatctta aggcgtaaat tgtaagcgtt 1080 aatattttgt taaaattcgc gttaaatttt tgttaaatca gctcattttt taaccaatag 1140 gccgaaatcg gcaaaatccc ttataaatca aaagaataga ccgagatagg gttgagtgtt 1200 gttccagttt ggaacaagag tccactatta aagaacgtgg actccaacgt caaagggcga 1260 aaaaccgtct atcagggcga tggcccacta cgtgaaccat caccctaatc aagttttttg 1320 gggtcgaggt gccgtaaagc actaaatcgg aaccctaaag ggagcccccg atttagagct 1380 tgacggggaa agccggcgaa cgtggcgaga aaggaaggga agaaagcgaa aggagcgggc 1440 gctagggcgc tggcaagtgt agcggtcacg ctgcgcgtaa ccaccacacc cgccgcgctt 1500 aatgcgccgc tacagggcgc gtcaggtggc acttttcggg gaaatgtgcg cggaacccct 1560 atttgtttat ttttctaaat acattcaaat atgtatccgc tcatgagaca ataaccctga 1620 taaatgcttc aataatattg aaaaaggaag agtcctgagg cggaaagaac cagctgtgga 1680 atgtgtgtca gttagggtgt ggaaagtccc caggctcccc agcaggcaga agtatgcaaa 1740 gcatgcatct caattagtca gcaaccaggt gtggaaagtc cccaggctcc ccagcaggca 1800 gaagtatgca aagcatgcat ctcaattagt cagcaaccat agtcccgccc ctaactccgc 1860 ccatcccgcc cctaactccg cccagttccg cccattctcc gccccatggc tgactaattt 1920 tttttattta tgcagaggcc gaggccgcct cggcctctga gctattccag aagtagtgag 1980 gaggcttttt tggaggccta ggcttttgca aagatcgatc aagagacagg atgaggatcg 2040 tttcgcatga ttgaacaaga tggattgcac gcaggttctc cggccgcttg ggtggagagg 2100 ctattcggct atgactgggc acaacagaca atcggctgct ctgatgccgc cgtgttccgg 2160 ctgtcagcgc aggggcgccc ggttcttttt gtcaagaccg acctgtccgg tgccctgaat 2220 gaactgcaag acgaggcagc gcggctatcg tggctggcca cgacgggcgt tccttgcgca 2280 gctgtgctcg acgttgtcac tgaagcggga agggactggc tgctattggg cgaagtgccg 2340 gggcaggatc tcctgtcatc tcaccttgct cctgccgaga aagtatccat catggctgat 2400 gcaatgcggc ggctgcatac gcttgatccg gctacctgcc cattcgacca ccaagcgaaa 2460 catcgcatcg agcgagcacg tactcggatg gaagccggtc ttgtcgatca ggatgatctg 2520 gacgaagagc atcaggggct cgcgccagcc gaactgttcg ccaggctcaa ggcgagcatg 2580 cccgacggcg aggatctcgt cgtgacccat ggcgatgcct gcttgccgaa tatcatggtg 2640 gaaaatggcc gcttttctgg attcatcgac tgtggccggc tgggtgtggc ggaccgctat 2700 caggacatag cgttggctac ccgtgatatt gctgaagagc ttggcggcga atgggctgac 2760 cgcttcctcg tgctttacgg tatcgccgct cccgattcgc agcgcatcgc cttctatcgc 2820 cttcttgacg agttcttctg agcgggactc tggggttcga aatgaccgac caagcgacgc 2880 ccaacctgcc atcacgagat ttcgattcca ccgccgcctt ctatgaaagg ttgggcttcg 2940 gaatcgtttt ccgggacgcc ggctggatga tcctccagcg cggggatctc atgctggagt 3000 tcttcgccca ccctaggggg aggctaactg aaacacggaa ggagacaata ccggaaggaa 3060 cccgcgctat gacggcaata aaaagacaga ataaaacgca cggtgttggg tcgtttgttc 3120 ataaacgcgg ggttcggtcc cagggctggc actctgtcga taccccaccg agaccccatt 3180 ggggccaata cgcccgcgtt tcttcctttt ccccacccca ccccccaagt tcgggtgaag 3240 gcccagggct cgcagccaac gtcggggcgg caggccctgc catagcctca ggttactcat 3300 atatacttta gattgattta aaacttcatt tttaatttaa aaggatctag gtgaagatcc 3360 tttttgataa tctcatgacc aaaatccctt aacgtgagtt ttcgttccac tgagcgtcag 3420 accccgtaga aaagatcaaa ggatcttctt gagatccttt ttttctgcgc gtaatctgct 3480 gcttgcaaac aaaaaaacca ccgctaccag cggtggtttg tttgccggat caagagctac 3540 caactctttt tccgaaggta actggcttca gcagagcgca gataccaaat actgtccttc 3600 tagtgtagcc gtagttaggc caccacttca agaactctgt agcaccgcct acatacctcg 3660 ctctgctaat cctgttacca gtggctgctg ccagtggcga taagtcgtgt cttaccgggt 3720 tggactcaag acgatagtta ccggataagg cgcagcggtc gggctgaacg gggggttcgt 3780 gcacacagcc cagcttggag cgaacgacct acaccgaact gagataccta cagcgtgagc 3840 tatgagaaag cgccacgctt cccgaaggga gaaaggcgga caggtatccg gtaagcggca 3900 gggtcggaac aggagagcgc acgagggagc ttccaggggg aaacgcctgg tatctttata 3960 gtcctgtcgg gtttcgccac ctctgacttg agcgtcgatt tttgtgatgc tcgtcagggg 4020 ggcggagcct atggaaaaac gccagcaacg cggccttttt acggttcctg gccttttgct 4080 ggccttttgc tcacatgttc tttcctgcgt tatcccctga ttctgtggat aaccgtatta 4140 ccgccatgca t 4151 

What is claimed is:
 1. A cDNA molecule encoding a fusion protein that comprises mammalian DHFR and a therapeutic protein.
 2. The cDNA of claim 1, wherein the fusion protein comprises a wild-type mammalian DHFR.
 3. The cDNA of claim 2, wherein the wild-type mammalian DHFR is rat, mouse, dog, monkey or human DHFR.
 4. The cDNA of claim 1, wherein the fusion protein comprises a mutant form of DHFR.
 5. The cDNA of claim 4, wherein the fusion protein comprises a mutant form of human DHFR.
 6. The cDNA of claim 5, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 7. The cDNA of claim 4, wherein the mutant form of human DHFR differs from wild-type DHFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 8. The eDNA of claim 7, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 9. The cDNA of claim 1, wherein the therapeutic protein is a protein that enhances toxicity of an administered drug.
 10. The cDNA of claim 9, wherein the therapeutic protein is a mutant or wild-type form of herpes simplex virus thymidine kinase.
 11. The cDNA of claim 10, wherein the fusion protein comprises a wild-type mammalian DHFR.
 12. The cDNA of claim 11, wherein the wild-type mammalian DHFR is rat, mouse, dog, monkey or human DHFR.
 13. The cONA of claim 10, wherein the fusion protein comprises a mutant form of DHFR.
 14. The cDNA of claim 13, wherein the fusion protein comprises a mutant form of human DHFR.
 15. The cDNA of claim 14, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 16. The cDNA of claim 13, wherein the mutant form of human DHFR differs from wild-type DHFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 17. The cDNA of claim 16, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 18. The cDNA of claim 9, wherein the therapeutic protein is cytosine deaminase.
 19. The cDNA of claim 1, wherein the therapeutic protein is a product of a pro-apoptotic gene.
 20. The cDNA of claim 19, wherein the fusion protein comprises a wild-type mammalian DHFR.
 21. The cDNA of claim 19, wherein the fusion protein comprises a mutant form of DHFR.
 22. The cDNA of claim 21, wherein the fusion protein comprises a mutant form of human DHFR.
 23. The cDNA of claim 22, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 24. The cDNA of claim 22, wherein the mutant form of human DHFR differs from wild-type DHIFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 25. The cDNA of claim 24, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 26. The cDNA of claim 1, wherein the therapeutic protein is a product of a tumor suppressor gene.
 27. The cDNA of claim 19, wherein the fusion protein comprises a wild-type mammalian DHFR.
 28. The cDNA of claim 27, wherein the fusion protein comprises a mutant form of DHFR.
 29. The cDNA of claim 28, wherein the fusion protein comprises a mutant fonrm of human DHFR.
 30. The cDNA of claim 29, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 31. The cDNA of claim 29, wherein the mutant form of human DHFR differs from wild-type DHFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 32. The cDNA of claim 31, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 33. The cDNA of claim 1, wherein the therapeutic protein is an immunostimulatory molecule.
 34. The cDNA of claim 33, wherein the fusion protein comprises a wild-type mammalian DHFR.
 35. The cDNA of claim 33, wherein the fusion protein comprises a mutant form of DHFR.
 36. The cDNA of claim 35, wherein the fusion protein comprises a mutant form of human DHFR.
 37. The cDNA of claim 36, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 38. The cDNA of claim 36, wherein the mutant form of human DHFR differs from wild-type DHFR as a result of one or more mutations, including at least one mutation at anamino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 39. The cDNA of claim 38, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 40. The cDNA of claim 1, wherein the therapeutic protein is a functional protein useful in gene therapy.
 41. The cDNA of claim 40, wherein the therapeutic protein is a wild-type or enhanced beta-globin protein.
 42. The cDNA of claim 1, further comprising a region encoding a reporter protein.
 43. The cDNA of claim 42, wherein the reporter protein is green fluorescent protein.
 44. A fusion protein that comprises mammalian DHFR and a therapeutic protein.
 45. The fusion protein of claim 44, wherein the fusion protein comprises a wild-type mammalian DHFR.
 46. The fusion protein claim 46, wherein the wild-type mammalian DHFR is rat, mouse, dog, monkey or human DHFR.
 47. The fusion protein of claim 44, wherein the fusion protein comprises a mutant form of DHFR.
 48. The fusion protein of claim 47, wherein the fusion protein comprises a mutant form of human DHFR.
 49. The fusion protein of claim 48, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 50. The fusion protein of claim 47, wherein the mutant form of human DHFR differs from wild-type DHFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 51. The fusion protein of claim 50, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 52. The fusion protein of claim 44, wherein the therapeutic protein is a protein that enhances toxicity of an administered drug.
 53. The fusion protein of claim 52, wherein the therapeutic protein is a mutant or wild-type form of herpes simplex virus thymidine kinase.
 54. The fusion protein of claim 52, wherein the therapeutic protein is cytosine deaminase.
 55. The fusion protein of claim 44, wherein the therapeutic protein is a product of a pro-apoptotic gene.
 56. The fusion protein of claim 44, wherein the therapeutic protein is a product of a tumor suppressor gene.
 57. The fusion protein of claim 44, wherein the therapeutic protein is an immunostimulatory molecule.
 58. The fusion protein of claim 44, wherein the therapeutic protein is a functional protein useful in gene therapy.
 59. The fusion protein of claim 58, wherein the therapeutic protein is a wild-type or enhanced beta-globin protein.
 60. The fusion protein of claim 44, further comprising a reporter protein.
 61. The fusion protein of claim 60, wherein the reporter protein is green fluorescent protein.
 62. A method for providing enhanced delivery of a therapeutic protein to a mammalian subject comprising the step of administering to the mammalian subject a cDNA molecule encoding a fusion protein that comprises mammalian DHFR and a therapeutic protein such that the cDNA molecule is expressed
 63. The method of claim 62, wherein the fusion protein comprises a wild-type mammalian DHFR.
 64. The method of claim 63, wherein the wild-type mammalian DHFR is rat, mouse, dog, monkey or human DHFR.
 65. The method of claim 62, wherein the fusion protein comprises a mutant form of DHFR.
 66. The method of claim 65, wherein the fusion protein comprises a mutant form of human DHFR.
 67. The method of claim 66, wherein the mutant form of human DHFR has increased resistance to methotrexate.
 68. The method of claim 66, wherein the mutant form of human DHFR differs from wild-type DHFR as a result of one or more mutations, including at least one mutation at an amino acid corresponding to amino acid 15, 22, 31 or 34 of the wild-type sequence.
 69. The method of claim 68, wherein the mutant form of human DHFR differs from wild-type human DHFR as a result of a set of mutations comprising a mutation at the amino acid corresponding to amino acid 22 and a mutation at the amino acid corresponding to amino acid 31 of the wild-type sequence.
 70. The method of claim 62, wherein the therapeutic protein is a protein that enhances toxicity of an administered drug.
 71. The method of claim 70, wherein the therapeutic protein is a mutant or wild-type form of herpes simplex virus thymidine kinase.
 72. The method of claim 70, wherein the therapeutic protein is cytosine deaminase.
 73. The method of claim 62, wherein the therapeutic protein is a product of a pro-apoptotic gene.
 74. The method of claim 62, wherein the therapeutic protein is a product of a tumor suppressor gene.
 75. The method of claim 62, wherein the therapeutic protein is an immunostimulatory molecule.
 76. The method of claim 62, wherein the therapeutic protein is a functional protein useful in gene therapy.
 77. The method of claim 76, wherein the therapeutic protein is a wild-type or enhanced beta-globin protein.
 78. The method of claim 62, wherein the fusion protein further comprises a reporter protein.
 79. The method of claim 78, wherein the reporter protein is green fluorescent protein. 